Read This if you have GM Oil Life Monitor

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324
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California
For some of you who owns GM car with oil life monitor and thinks that changing oil every 3000 miles is a right thing to do this information could be useful. Part of this article is taken from GM Techlink November 2001 edition. I assume that they talk about conventional dyno oil, except where synthetic is recommended (Corvette). " ... Briefly, engine oil degrades in a predictable fashion, according to several measurable engine operating conditions. The engine control module counts combustion events (measured in rpm) and reads coolant temperature. From these numbers, the computer is able to track oil deterioration and notifies the driver when a change is needed. The best value from the cost of an oil change is obtained by maximizing the mileage between changes, so long as there is no adverse effect to the engine. With the GM oil life system, the average person can expect oil change intervals of 4000-7000 miles for mixed driving, and 7000 to 10000 miles for highway driving, while the Chevrolet Corvette and the 2002 Envoy, Bravada and TrailBlazer can achieve 15000 miles under ideal conditions. ... There’s a lot of information on vehicle maintenance shared on consumer-oriented websites – some correct, come erroneous, and some simply outdated. For instance, conventional wisdom calls for oil changes every 3000 miles. Not surprisingly, this conservative figure is also supported by those who derive income from selling oil changes. Many of your customers have become convinced that any longer oil change interval is somehow harmful to their engine. At the retail level, you can do your part by promoting proper use of the GM oil life system. Become familiar with its function, and be prepared to help customers understand that observing the monitor’s recommendation is the easiest way to take the guesswork out of oil change intervals. It also ensures that they are giving their vehicle the proper care it deserves, at the minimum expense." [ July 07, 2003, 03:20 AM: Message edited by: Titanium_Alloy ]
 
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401
Location
Largo, FL
So the GM Oil Life Monitor is attempting to quantify some of the factors which contribute to oil degradation. This is a good idea. However, they're making the assumption that all oils will degrade at a uniform rate when subjected to the same conditions, which we all know not to be the case. I think it's a step in the right direction, and it will be interesting to compare some UOAs to see how conservative the monitor is.
 
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1,856
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PA
Remember though that this oil life system was developed not by oil companies but by GM. GM is in it to sell cars right? Okay, well lets put conventional oil in all the cars and run it 8,000 miles per cycle til the oil is dead as a doorknob. The Oil companies make less money because there are fewer oil changes... GM makes more money because your beloved car is worn out in 100K miles and you go buy a new one. [Roll Eyes] If I'm going to run longer intervals, I'll do it scientifically using oil analysis and by trying different oils. GM loves to say silly things like "Dexcool is good for 150,000 miles! Fuel Filter? You don't need to change that for the life of the car! Wax the car? No need... we have PERFECT paint which ALWAYS repels water [Roll Eyes] etc etc." If these things were true, it would be great. It isn't true, we know it, and thats why we do 30K maintenance and wax our cars and try to keep them in perfect condition... or at least some of us do [Big Grin] [Duh!] [Cheers!] [ July 07, 2003, 07:46 AM: Message edited by: Dominic ]
 
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3,023
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USA-Michigan
Here's more info from the May 2003 edition..
quote:
How often should engine oil be changed? - 3,000 miles (5000 km) - 5,000 miles (8000 km) - 7,500 miles (12000 km) - 10,000 miles (16000 km) Actually, all of these are correct, depending on operating conditions. Oil life is affected by many factors other than just miles driven. The type of driving, temperature, and engine load all play a part. That’s why GM has developed the GM Oil Life System, an electronic watchdog that keeps track of all these variables and notifies the driver when it’s time to change oil. (fig. 1) We first told you about the GM Oil Life System in the March 2000 TechLink. Since then, the system has become standard equipment on nearly all GM products. Briefly, the Oil Life System is programmed with a certain number of engine revolutions. As the engine runs, this number is reduced until it reaches zero, and the Oil Life light or message comes on. But there’s more. Operating the engine under low or high temperatures, and under high load conditions subtracts (penalizes) extra revolutions, so the light comes on sooner. Changing engine oil according to actual need rather than an inflexible schedule provides several benefits. First is simpified determination about when to change oil. No more decisions about “normal” conditions vs. “severe” conditions. Second is reduced operating costs for GM’s customers, who now have to change oil only when it’s needed. Third is minimizing the amount of used oil that must be disposed of. And fourth, engines will always be running with sufficiently fresh oil, for long life. These benefits will be realized only if engine oil is actually changed as indicated by the GM Oil Life System. Some customers “get it” when it’s explained to them. Others may be reluctant to deviate from traditional oil change interval charts. So, part of the responsibility falls on retail service people to help get the message out. TIP: To help you do this, an IDL broadcast is being prepared. Consult the GM Training Program Guide and Schedule for “Understanding the GM Oil Life System” (PPS03.P1D). There’s More Traditionally, the vehicle maintenance schedule has been based on miles or time, while the oil change interval is now based on the GM Oil Life System. This could result in customers having to bring their vehicles in for an oil change when the light comes on, only to find that the vehicle is due in a month for scheduled maintenance. That’s all changing. In the accompanying article “Simplified Maintenance Schedules”, you’ll learn how maintenance intervals are now being tied into the oil change intervals indicated by the Oil Life System.
and some more info
quote:
New and simplified maintenance schedules are coming for 2004. Historically, maintenance schedules have been regarded as complicated, extensive, and in some cases confusing to customers. In fact, there have been two separate schedules from which a choice must be made. The short trip/city schedule was defined by a list of conditions, including trips below 5 miles (8 km), extensive idling, and others. This schedule called for performing certain operations such as oil changes at fairly low intervals. A long trip/highway schedule was defined simply as only if none of the short trip definitions applied. And the service intervals were longer. In addition, these schedules called for performing various operations according to mileage and/or time. And, maintenance schedules required literally dozens of pages to describe fully in the owner’s manual. All of this is changing on those vehicles equipped with the GM Oil Life System. First and foremost, oil changes are now done according to the GM Oil Life System, which is explained in an accompanying article, “GM Oil Life System Revisited.” Equally important, all other maintenance items are being keyed to the oil change intervals. Refer to individual vehicle maintenance schedules for specific requirements. Refer to (fig. 2), How Driving Style Affects Oil Life. A - Mileage Between Oil Changes B - Long Trip C - Short Trip D - Engine Temperature E - Cold F - Hot G - Typical Driver H - Trips Less Than 2 Miles (3.2 km) J - Highway Driving K - Trailer Towing Scheduled Maintenance When the CHANGE ENGINE OIL light or message comes on, it means that service is required on the vehicle. It should be serviced as soon as possible within the next 600 miles (1000 km). It is possible that, under the best conditions, the engine oil life system may not indicate that vehicle service is necessary for over a year. However, engine oil and filter must be changed at least once per year, and at this time the system must be reset. NOTICE: The owner should check oil regularly and keep it at the proper level. Failure to keep the oil at the proper level can cause damage to the engine not covered by warranty.
[ July 07, 2003, 07:50 AM: Message edited by: Mike ]
 
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1,856
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PA
Hey Mike.. my oil change total runs me $12 on my GM car. If I drive 12,000 miles per year 3,000 mile changes = $48.00 7,500 mile changes = $20.00 So, using the oil life system, I save $28/yr. I can think of better ways to save money, like buying cheaper cereal at the grocery store [Big Grin]
 
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1,432
Location
Virginia
I think this system is a big step in the right direction. Everyone says that changing your oil every 3K whether you need it or not is "cheap insurance". At the micro level, sure it is. Just multiply it by a hundred million vehicles and we are drowning (unnecessarily) in used oil. My car has been running various synthetics for the last 30K miles (now has about 55K on it). In the interest of science I'm thinking of running dino 5W-30 using the oil change system and posting the analysis to see just how bad the oil is when they say to change it. If GM is screwing all its customers we'll know soon enough. Plus when my Chevy goes out in a big cloud of blue smoke I can get the Honda Accord that I really want... Matt
 
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3,683
Location
Chattanooga, TN
I have the oil life system on my 2000 Buick with a maximum interval of 7500 miles before it activates the light. My experience, I run 12,000 mile change intervals using Amosil 10W30. At about 6500 miles I reset the interval however, at that time the monitor shows about 20-30% oil life left. Oil analysis has been fine so it appears that it may work in this situation. (not a perfect test obviously) However, the GM 3800 series engine is easy on oil, old push rod design. I wish someone would inform the Buick dealer that the monitor is to be followed though, I keep getting notices for the 3000 mile changes.
 

Al

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19,167
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Elizabethtown, Pa
quote:
Originally posted by Matt89: If GM is screwing all its customers we'll know soon enough. Plus when my Chevy goes out in a big cloud of blue smoke I can get the Honda Accord that I really want... Matt
[Off Topic!] We already know-they have. Look at the Intake manifold gaskage leakage problem. Its universal in the 3.1/3.4. GM refuses to even recognize it. They spent gazillions developing dex-cool to hide rather than fix the problem and take care of their customers. [crushedcar] [ July 07, 2003, 09:02 AM: Message edited by: Al ]
 
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1,432
Location
Virginia
Not to mention the nice underbody/structural rust that I see getting started on my 3 1/2 year old car. Looks like oil change intervals will be the least of my worries...
 
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688
Location
Morgantown, WV
Mine kicks on every 5,000 miles or so, which is about right for dino oil. I don't see what the big deal is. [Roll Eyes] It's not the '60s anymore. I wonder how long it took people to accept 3k oil changes. Probably a whole bunch of people going "well I always changed my oil every 1k and my 1940 Chevy ran fine for 20 years that way so I'm gonna keep doing it every 1k." You really think GM is trying to make their cars blow up in 100,000 miles so you'll buy another? WOULD you buy another car by the same company if your first one was dead in 100k?? Do you really think GM thinks you will?? That is ridiculous conspiracy theory garbage. Cheers, 3MP
 
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1,908
Location
Fort Worth, TX
It's a damned good idea, and about time. " . . counts combustion events" and " . . a certain number of engine revolutions" sounds no more problematic to me as a way of predicting service intervals than what went previously; in fact it appears ideal as a starting point especially in making it the basis of all service intervals otherwise based on time/mileage. It removes some of the third item -- conditions -- as a wildcard. I'm still not sure how sophisticated this monitoring system is (despite doing some reading on it beyond what is shown here), but it is a big step in the right direction for the vast majority of drivers. I would be pleased to have it on a new car as an additional input. If I read it correctly, then 7500 miles is likely the maximum the owner will see (with the noted cars excepted). Thanks for providing the info.
 
Actually, a lot of people have been conditioned to believe that 100,000 miles is still an amazingly high mileage for a car to accrue. Most of us on this website know better, but much of the public do not. This misconception is backed up by a lot of commercials. For example, the high-mileage oils imply in their TV ads that at 75,000 miles or so, your engine is getting over the hill and it's time to use this magic elixir oil to keep the old thing running. But heck, for me 75,000 miles is simply two years' mileage. And I'll use my synthetic (Red Line) in preference to any "high-mileage" stuff in my 220,000-mile Escort wagon. Keep in mind that well until the 1970s, 40,000 miles was still considered a lot. Most dealers won't accept a vehicle with more than, say, 50,000-60,000 miles as a trade-in. The misconceptions continue. As for me, I'd take a well-maintained car with 150,000 miles over a car with 50,000 miles that has had lackadaisical "care" and 10,000-mile oil changes. So yes, I think--simply my opinion--that GM is being a bit cynical with this oil life system and probably does expect the engine to give out at roughly 100K with the system anyway. And many people really won't know better but will buy another GM product, figuring that 100K was a reasonable lifetime for the engine based on what they see and hear. I suspect that similar considerations apply with Ford and its widespread conversion to thin, thin 5W20 in its new cars/engines. "But it's for fuel economy!" Right. Ford and GM want to sell you, if not a whole new vehicle, then at least a quality rebuilt engine at 100K miles. Ha ha. [ July 07, 2003, 09:46 AM: Message edited by: ekrampitzjr ]
 
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5
Location
Auburn Hills, MI
quote:
Originally posted by Dominic: Hey Mike.. my oil change total runs me $12 on my GM car. If I drive 12,000 miles per year 3,000 mile changes = $48.00 7,500 mile changes = $20.00 So, using the oil life system, I save $28/yr. I can think of better ways to save money, like buying cheaper cereal at the grocery store [Big Grin]
Hi Dominic, My wife and I put in ~60k miles a year on both of our cars. Guess what, I am the one responsible for maintenances of both vehicles. I just don't have time to stop by the dealership or a quick lube place twice/month, if I change oil every 3k miles for both vehicles. It is not only the money that I saved but also the time and hassle. Currentyl, I am having an oil change interval of 7500 miles. I am using Mobil 1. Pending an oil analysis, I might extend it to 10k miles interval. This will really save me a lot of time compared to changing every 3k miles.
 
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8,756
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RI
I'd love to see GM's software for the oil life monitor. Anyone want to gamble that it is nothing but an engine timer? Best value? Cost? Whats a good value on a new engine? Cost to install it? I hate when OEM's always toss in value/cost.....If they want to give us a good value, give us a million mile powertrain warranty and quit trying to save us $20 a year. Either that or make sure the dealer performs warranty work without first trying to void it. Funny, I don't derive my income from selling oil. Not enough profit when considering all those jippyloobs out there. But, I still recommend 3k changes for everyone. I spent $1000 on gas plus $40 on oil changes last year. Thats $1040. I guess that the oil companies really wanted $1040 instead of $1020 from me for the extra $20 from one extra oil change [Confused] I wonder if that extra $20 that I spent is why I've never sludged up an engine and never had any engine mechanical problems. Since a lot of people are too ignorant and lazy to check their oil levels, most cars can make it to 3k miles without running dry. Extended oil intervals aren't for the normal average lazy consumer.
 

CJH

Messages
489
Location
Pennsylvania
Here's how I look at the GM oil-monitoring system... When making the decision about when to change your oil, more information is better than less information (just like any other decision). On one hand, we can make the decision traditionally by time / mileage (e.g. 3 months or 3,000 miles), or we can use the number of combustions and engine temperature history. Intuitively, it is obvious to me which of these is a better indicator or oil life. True, different oils degrade at different rates. The GM system is obviously set up using your typical dino oil and is probably set conservatively, just as the 3,000 / 7,500 intervals are. While not as good as a (theoretical) oil sensor that could measure contaminants and viscosity change, it is far better than just depending on time / mileage alone. For most cars, most of the time the light comes on between the traditional severe and normal intervals of (typically) 3,000 and 7,500 miles. Most people do a combination of short trips and highway driving, so it is sometimes hard to say whether you should use the normal or severe schedule, and some people naturally say...if I do the most, then I know I am ok. Well, this oil change light is a tool to help you decide where you fall between normal and severe conditions. How can you argue with basing the oil change interval decision on better information? I own 3 GM cars and have lots of criticisms of GM, but this light is not one of them. We need to get away from the 3,000 mile tradition. Like someone pointed out, it does not save a ton of money, but it does take time and it does add up. Maybe the time and money could be better spent in improving maintenance in other areas of the car, such as checking tire pressures more frequently, monitoring and changing engine coolant more frequently, or changing brake fluid.
 
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4,805
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Lakeville, MN
I'd hardly bet the oil monitor is conservative. One of my relatives with a Trailblazer had the change light come on for the first oil change at about 13,000 miles. That on the facory dino fill. Second time it came on was roughly another 13,000 miles later through a Minnesota Winter, which absolutely destroys oil. Instead its seen regular 3,000-4,000 mile changes, done by the owner. He didn't even know it had the monitor until the light came on the 1st time. Based on what we've seen out of some dino 5w30 analysis results, I'd hate to see this oil at 13,000 miles. Would you?
 

Titanium_Alloy

Thread starter
Messages
324
Location
California
God is my witness. I didn't want to post this reply but... Here are some thoughts: If you “3000 miles” people change you synthetic (or even dino) oil at 5000 miles (which is not a problem for synthetic, it could easily go 10000 miles or more as recommended everywhere else in the world) you will need only 2 oil changes for 10000 miles instead of 3. We have 1783 active members on this forum. If 300 members will do 5000 miles (or more) change interval instead of 3000, we save on average: 300 cars * 5 quarts of oil = 1500 quarts of oil On http://www.recycleoil.org/benefits_of_recycling.htm we can find that: “Recycling the motor oil from one oil change protects a million gallons of drinking water – or a year’s supply for 50 people.” So we can protect about 300,000,000 gallons of clean drinking water. If every one of 300 people donates money saved from extra oil changes to some kind of charity for let’s say hungry children, charity gets: 1500 quarts of oil * 1 dollar = 1500 dollars for dino oil 1500 quarts * 5 dollars = 7500 dollars for synthetic oil How many children in other countries do you think charity can feed even for $5000? Besides, if you don’t like giving money to charity, why should you give extra money to oil moguls? Those are the guys who drive $100,000 dollar Mercedes and own $300,000 dollar Ferrari. Those are the guys who charge you $1.90/gallon for regular fuel (at least here in CA). Those are the guys who own multimillion dollar mansions and private jets. Those are the guys who screw you and you paying them (in this case you pay for extra oil) to do so. No matter what some of you say, 5000 or even 7500 miles on good oil can’t really harm your car if you don't rev up engine all the time.
 
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418
Location
OR
I have one of these oil life monitors in my GTP. I have zero confidence in GM's algorithm. IMHO GM underestimates all of these mainainance intervals because they can pander to the environazis and at the same time claim some marketing benefit. The don't have to worry about the consequences due to their crappy 3 yr 36kmi warranty. My owners manual claims no tranny fluid changes need to be done until 100kmi, coolant lasts 5yr/150k miles, and supercharger oil never needs changing. This is all hogwash. At 35kmi I'm glad I changed my tranny fluid because they old stuff smelled burnt. The Dexcool claim is fueling class action lawsuits and no-one believes their supercharger oil claim. I choose to change oil at 5kmi (Mobil 1) and it's served me well.
quote:
Originally posted by Titanium_Alloy: For some of you who owns GM car with oil life monitor and thinks that changing oil every 3000 miles is a right thing to do this information could be useful. Part of this article is taken from GM Techlink November 2001 edition. I assume that they talk about conventional dyno oil, except where synthetic is recommended (Corvette). " ... Briefly, engine oil degrades in a predictable fashion, according to several measurable engine operating conditions. The engine control module counts combustion events (measured in rpm) and reads coolant temperature. From these numbers, the computer is able to track oil deterioration and notifies the driver when a change is needed. The best value from the cost of an oil change is obtained by maximizing the mileage between changes, so long as there is no adverse effect to the engine. With the GM oil life system, the average person can expect oil change intervals of 4000-7000 miles for mixed driving, and 7000 to 10000 miles for highway driving, while the Chevrolet Corvette and the 2002 Envoy, Bravada and TrailBlazer can achieve 15000 miles under ideal conditions. ... There’s a lot of information on vehicle maintenance shared on consumer-oriented websites – some correct, come erroneous, and some simply outdated. For instance, conventional wisdom calls for oil changes every 3000 miles. Not surprisingly, this conservative figure is also supported by those who derive income from selling oil changes. Many of your customers have become convinced that any longer oil change interval is somehow harmful to their engine. At the retail level, you can do your part by promoting proper use of the GM oil life system. Become familiar with its function, and be prepared to help customers understand that observing the monitor’s recommendation is the easiest way to take the guesswork out of oil change intervals. It also ensures that they are giving their vehicle the proper care it deserves, at the minimum expense."
 
Messages
4,805
Location
Lakeville, MN
quote:
Originally posted by Titanium_Alloy: No matter what some of you say, 5000 or even 7500 miles on good oil can’t really harm your car if you don't rev up engine all the time.
Never mind those pesky UOA's that have shown many oils and engine combinations are not good past 3 or 4000 miles. Or ignore the service intervals, which in many cases are still 3,000 miles under the severe duty schedule. One other assumption you made is that ALL of the oil from these changes will contaminate water. Given the thoughtful nature of the folks on this board, I highly doubt these people are the ones who need educating about proper oil disposal or extended oil change intervals -when appropriate.
 
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